12. Clear Lake
holds two hundred fifty and 9/10 acre feet of water. Lake Sonoma
holds eighteen and 4/5 acre feet. How many Lake Sonomas will it take
to fill Clear Lake?

How many times will 18 and 4/5 go into 250 and 9/10?

We are dividing mixed numbers so turn them into improper
fractions.

Invert and multiply

The 5 will cancel with the 10, but we should decide if the 2509
will cancel with the 94. Well, 94 = 2x47, so the only primes that go
into 94 are 2 and 47. 2 doesn't go into 2509 because 2509 is an odd
number, and you can check to find out that 47 does not go into 2509
either, so they don't cancel. Our answer is then 2509/188. This is
one instance where a mixed number would be more meaningful than an
improper fraction. Divide the bottom into the top.

so there would be enough water in Clear Lake to fill up Lake
Sonoma 13 and 55/188 times.